Comparitive Vertebrate Anatomy

Front 1

Chordates

Back 1

Notochord, DHNC, endostyle, post-anal tail, pharyngeal slits

Front 2

Urochordates

Back 2

tunicates, larvacea

Front 3

Cephalochordates

Back 3

Amphioxus

Front 4

Vertebrates

Back 4

Cranium w/ 3-part brain, vertebrae, neural crest cells, epidermal placodes, bone

Front 5

Agnathans

Back 5

Jawless forms

Front 6

Haikouella, Haikouichthyes

Back 6

Cambrian fossils representing early stages in vertebrate evolution

Front 7

Myxinoidea

Back 7

Hagfish. 1 semi-circular canal, no bone

Front 8

Petromyzontida

Back 8

Lampreys. Blood sucking parasites, 2 semicircular canals, potential for bone

Front 9

Conodonts

Back 9

fossil forms with odd tooth-like structures, no jaws

Front 10

Ostracoderms

Back 10

Extinct armored, jawless fishes (2-semicircular canals with lampreys

Front 11

Gnathostomes

Back 11

jaws, 2 sets of appendages, 3 semicircular canals, paired nostrils

Front 12

Placoderms

Back 12

hinged heat/thoracic shields, jaws but no teeth.

Front 13

Chondrichthyes

Back 13

cartilaginous fishes, good senses, long gestation, big brains

Front 14

Acanthodians

Back 14

Spiny forms, big eyes, short snouth, subterminal mouth

Front 15

Osteichthyes

Back 15

bony fish, swim bladder/lungs

Front 16

Actinopterygians

Back 16

ray-finned fish

Front 17

Palaeonscoids

Back 17

Primitive forms of actinopterygians. Sturgeons, paddlefish, birchirs

Front 18

Neopterygians,

Back 18

includes holosteans, like bowfin and gar

Front 19

Teleosts

Back 19

Advanced bony fish

Front 20

Sarcoterygians

Back 20

Fleshy-finned fish and tetrapods

Front 21

Coelacanths

Back 21

Only living form is latimeria

Front 22

Dipnoans

Back 22

lungfish

Front 23

Rhipidistians

Back 23

Fish forms ancestral to all tetrapods

Front 24

Tetrapods

Back 24

Four limbs

Front 25

Labyrinthodonts

Back 25

Acanthostega, Ichthyostega, and primitive forms

Front 26

Lepospondyles

Back 26

More basal tetrapods

Front 27

Lissamphibia

Back 27

Amphibians (Pedicellate teeth, auricular operculum)

Front 28

Anura

Back 28

Frogs

Front 29

urodela

Back 29

Salamanders

Front 30

Gymnophiona

Back 30

Burrowing forms. Caecilians

Front 31

Amniotes

Back 31

Cleidodic eggs, 2 sacral vertebrae, horny scales

Front 32

Sauropsida

Back 32

Reptiles

Front 33

Anapsids

Back 33

Primitive skull w/ no openings. Turtles

Front 34

Diapsides

Back 34

2 pairs of skull openings-lower and upper temporal fenestrae. Misc. aquatic forms, lizards, crocodiles, dinosaurs, birds.

Front 35

Lepidosaurs

Back 35

Sphenodon-primitive lizard-like animal from New Zealand

Front 36

Squamates

Back 36

Lizards, snakes, amphisbaenians (loss of lower temporal bar)

Front 37

Archosaurs

Back 37

Antorbital fenestra=opening in front of eye

Front 38

Crocodilians

Back 38

Member of diapsides

Front 39

Pterosaurs

Back 39

Extinct flying reptiles

Front 40

Dinosaurs

Back 40

(Upright stance and associated skeletal changes)

Front 41

Birds

Back 41

Powered flight

Front 42

Synapsides

Back 42

Mammals and their ancestors (1 pair of temportal fenestra)

Front 43

Pelycosaurs

Back 43

Basal synapsidds including dimetrodon and other sailbacks.

Front 44

Therapsids

Back 44

Diverse mammal-like precursors

Front 45

Mammals

Back 45

Hair, mammary glands, sweat glands, sq. dent jaw joint, 3 ear bones

Front 46

Monotremes

Back 46

Egg laying mammals, platypus, echidnas,

Front 47

MetaTheria

Back 47

Marsupials-possums to kangaroos

Front 48

Eutheria

Back 48

Placental mammals